Would like to know the general opinion on the likelihood of Fuji producing a full frame model similar to my X100 with fixed lens. Will appreciate your thoughts.

You should ask yourself the question, how big is the probability that Fuji will release a whole new line of lenses including a roadmap for those lenses?I am not saying that Fuji will never produce one, but chances that they will introduce a FF system in the near future are probably not really large.